50 - 54 mpg in a non diesel/non hybrid.


gnasher729

macrumors P6
Nov 25, 2005
16,497
3,094
2005 Chevy Cobalt 2.2L 5 speed.
What kind of gallons (US or UK)? What kind of weather - that can make 20% difference. And constant 30mph? Where can I drive constant 30mph over any length of time? So they probably picked the speed where the engine is just about capable of running at lowest possible revs in a high gear, with no power for acceleration at all. Call me when they can do 50 US mpg under realistic conditions.
 

SpookTheHamster

macrumors 65816
Nov 7, 2004
1,489
0
London
Well done, all you did is prove that economy tests are carried out in different conditions to that video. If you put a diesel or hybrid in those conditions it would still probably be more efficient than your Cobalt.

I hired a car with an instant fuel economy readout a couple of weeks ago, in certain conditions it was capable of 999mpg.
 

Wheaty

macrumors regular
Mar 6, 2009
146
0
Cheshire, UK
Agreed.


I would be more interested to know how well your economy does over a full tank of fuel with a change of driving style.. ie, not hard on the gass all the time... etc etc..

The How what where and when of driving makes a HUGE difference... during my typical tank of fuel I will get about 330miles, but over long distances on motorways, I'll get 400-440... which is a big jump in ecomomy. And if I drive like a nutter about 250.

So your 50+ Mpg, well done. but for how long can you keep it up!?

Wheaty
 

SactoGuy18

macrumors 68030
Sep 11, 2006
2,737
242
Sacramento, CA USA
If you know how to do hypermiling, you can squeeze some amazing fuel economy figures out of almost any car. I've read some people taking a 2010 Corvette Z06 sports car and getting around 40 miles per US gallon fuel economy (!), mostly because the Corvette drivetrain actually is very fuel efficient if you are gentle on acceleration and steady driving.
 

yg17

macrumors G5
Aug 1, 2004
14,888
2,480
St. Louis, MO
Instant MPG is worthless. It does not mean your car is capable of getting 54 MPG.

I can get my instant MPG into the 70s. I still only get around 31-32 highway.
 

velocityg4

macrumors 601
Dec 19, 2004
4,598
1,184
Georgia
If you know how to do hypermiling, you can squeeze some amazing fuel economy figures out of almost any car. I've read some people taking a 2010 Corvette Z06 sports car and getting around 40 miles per US gallon fuel economy (!), mostly because the Corvette drivetrain actually is very fuel efficient if you are gentle on acceleration and steady driving.
Well you have to consider that the Corvette is in the same weight range as many lighter cars. It only weighs about 400lbs more than a Honda Insight and about 100lbs more than a Prius. Another feature of the Corvette is that it is quite aerodynamic. Both of these factor a great deal in fuel economy.

If you ever noticed if you look at different engine sizes of one make and model of car there is rarely more than a nominal difference in the MPG rating of 1 maybe 2 MPG (usually the 2 MPG is in part due to a weight shift say from a V6 to a V8), though the bigger engines can certainly use a lot more if you have a lead foot. The only real differences become noticeable when switching from gas only to diesel or hybrid. Though the real gains for hybrids are in city driving.

If you want really fuel efficient strip out the crash cage, airbags and other safety features. Then also remove all the stuff in the engine compartment that is not actually needed to make a functioning car. Then you will get great fuel economy even from a gas engine. Though I would not want to be in that car with any other drivers on the road.
 

waloshin

macrumors 68040
Original poster
Oct 9, 2008
3,167
66
Well done, all you did is prove that economy tests are carried out in different conditions to that video. If you put a diesel or hybrid in those conditions it would still probably be more efficient than your Cobalt.

I hired a car with an instant fuel economy readout a couple of weeks ago, in certain conditions it was capable of 999mpg.
In that case the fuel injectors shut off.

What kind of gallons (US or UK)? What kind of weather - that can make 20% difference. And constant 30mph? Where can I drive constant 30mph over any length of time? So they probably picked the speed where the engine is just about capable of running at lowest possible revs in a high gear, with no power for acceleration at all. Call me when they can do 50 US mpg under realistic conditions.
Us gallons, 7 Celsius, and in my city the lights are setup that if your lucky you will get all green or if your not all red.
 

Wheaty

macrumors regular
Mar 6, 2009
146
0
Cheshire, UK
If you want really fuel efficient strip out the crash cage, airbags and other safety features. Then also remove all the stuff in the engine compartment that is not actually needed to make a functioning car. Then you will get great fuel economy even from a gas engine. Though I would not want to be in that car with any other drivers on the road.
Very true! I also own a 38yr old Land rover. Most people here in the UK cringe at that "oh my god what a guzzler :eek:" however I used to regularly get 22mpg out of its 2.25Lr engine, and the fact its not exactly aerodynamic! And how many manufacturers have cars are on the market still today that will still only do about 22mpg? Quite alot.. Mini's, BMW's, Fords, Audi's, Honda's, Subarus, Nissans..:confused:.. All far more aerodynamic, all far more sophisticated engines, all producing more than twice oomph than my landy and all with enough electrical bolt on gismos to need an alternator that can produce 3 times the power output.

Just think, what would be technically possible, if we lived with a bit more moderation, less of the air con, less of the 100W stereo's, a bit less of the crash protection because we not all rushing around excited by our 120BHP+ acceleration.... 50mpg would be a piece of cake!

But will we.... Of course not! we love our cars too much. We love the blinky lights on the stereo, or the air con in the summer, or the slight screechy noise the tyres make around entertaining twisty bits.

The MPG we get from our cars is as much of a cultural battle as a technological one.

Wheaty

..And I'm just as guilty as every one else.
 

SpookTheHamster

macrumors 65816
Nov 7, 2004
1,489
0
London
Like when...

Cruising down a huge slope?

Of course it can, there's nothing amazing about it :rolleyes:
In that case the fuel injectors shut off.
Seems like my point may have missed you two. If you drive a car in a different situation to how its mileage was tested, you will get a different result. If you drive at a constant 30mph on a flat/slight downhill there is almost no load. Do it in a diesel and you'll get an even better result.
 

steve2112

macrumors 68040
Feb 20, 2009
3,023
6
East of Lyra, Northwest of Pegasus
Very true! I also own a 38yr old Land rover. Most people here in the UK cringe at that "oh my god what a guzzler :eek:" however I used to regularly get 22mpg out of its 2.25Lr engine, and the fact its not exactly aerodynamic! And how many manufacturers have cars are on the market still today that will still only do about 22mpg? Quite alot.. Mini's, BMW's, Fords, Audi's, Honda's, Subarus, Nissans..:confused:.. All far more aerodynamic, all far more sophisticated engines, all producing more than twice oomph than my landy and all with enough electrical bolt on gismos to need an alternator that can produce 3 times the power output.

Just think, what would be technically possible, if we lived with a bit more moderation, less of the air con, less of the 100W stereo's, a bit less of the crash protection because we not all rushing around excited by our 120BHP+ acceleration.... 50mpg would be a piece of cake!

But will we.... Of course not! we love our cars too much. We love the blinky lights on the stereo, or the air con in the summer, or the slight screechy noise the tyres make around entertaining twisty bits.

The MPG we get from our cars is as much of a cultural battle as a technological one.

Wheaty

..And I'm just as guilty as every one else.
That always used to amaze me. Back in college, I owned a 1983 Nissan extra cab truck. It got 25+ MPG on the highway, even when it had 180k+ miles.

Part of the problem is what you mentioned: all the extra stuff thrown in today's cars. Another problem is they keep getting bigger and bigger. The current Honda Civic, for example, is about the same size as the Accord from the early 90s. For fun, compare a late 90s Nissan Altima to a current gen Altima. Finally, the government keeps getting into the act. Things like side-impact standards, mandated airbags, front impact standards, etc, have all added lots of weight to modern cars.

And the extra power is part of the problem. Realistically, there is no reason for a mid-sized sedan to have 250+ horsepower, which is the standard now for V6 powered sedans. We Americans love our power. :) I can't say anything, though. I miss my old car and its V6. And really, the penalty for that V6 wasn't that bad. My old Mazda 6 got 27MPG on the highway. My current Protege gets 31, and has 90 less HP. Not too bad of a penalty for that much more power.

Edit: Forgot to include a link on hypermiling. 59 MPG from an Accord!
 

tman07

macrumors regular
Mar 4, 2009
185
1
i dont want to seem like a doucher, but i could probably get 60+mpg going 30 mph in my 4 door honda civic ex.

Its really not that special, considering there is no where this is actually feasible...

Heck, i get 30+mpg normal driving with front breaks that are rubbing. yeah- getting that fixed this weekend.. haha (roters are shotttt)
 

ethical

macrumors 68000
Dec 22, 2007
1,661
1
Anybody watch the Top Gear episode where Jeremy Clarkson drove an Audi A8 800 miles on a single tank? The was pretty cool, he was running on fumes the last couple dozen miles.
 

tman07

macrumors regular
Mar 4, 2009
185
1
Anybody watch the Top Gear episode where Jeremy Clarkson drove an Audi A8 800 miles on a single tank? The was pretty cool, he was running on fumes the last couple dozen miles.
Actually, I thought they emptied his tank and found he could have gone another 100 or so miles? It was something crazy like that. Maybe im wrong or thinking of another episode?

**EDIT: I was thinking of a different episode, season 12 episode 4; Economy Run. Different from what you were thinking of. my baddd
 

ucfgrad93

macrumors P6
Aug 17, 2007
17,525
8,142
Colorado
So they probably picked the speed where the engine is just about capable of running at lowest possible revs in a high gear, with no power for acceleration at all. Call me when they can do 50 US mpg under realistic conditions.
Agreed. This is nice to show what it is capable of, but it could never happen in real world driving.
 

Ttownbeast

macrumors 65816
May 10, 2009
1,135
0
The standard Geo metro I-3 cylinder 1 liter gasoline engine was capable of 51 mpg on the highway back in the day...very little HP at around 49 but still pretty impressive economy wise and got 43 mpg city driving.

I have managed to tune and squeeze 30 mpg highway out of a small 1/2 ton pickup truck in my time on gasoline--the Chevy LUV I owned was a surprisingly versatile vehicle.
 

Wheaty

macrumors regular
Mar 6, 2009
146
0
Cheshire, UK
Edit: Forgot to include a link on hypermiling. 59 MPG from an Accord!
Interesting Link.

I assume by engine off he means out of gear, not Engine off.. If you switch of the engine on most cars you would loose power stearing, power assisted brakes, ABS, and numerous other saftery features that may be taking power from the engine. Not a good idea.

Although I a gree with the general idea that keeping the momentum constant is the best way to consever fuel.

Wheaty
 

IntheNet

macrumors regular
Oct 6, 2009
190
0
The standard Geo metro I-3 cylinder 1 liter gasoline engine was capable of 51 mpg on the highway back in the day...very little HP at around 49 but still pretty impressive economy wise and got 43 mpg city driving.
Simple physics here; reduce car weight and achieve better mileage. When you can't reduce any more weight of existing car materials you can re-manufacture the materials to make them lighter, again providing better mileage. The trouble with all this is that in addition to providing better mileage, you also achieve a far more dangerous vehicle in a collision, since the crumble zones disappear, making the vehicle not safe at any speed, but it achieves good mileage! You trade one thing (safety) for another (mileage). Chances are that a vehicle that obtains 50-54 mpg will be lethal in an accident; moreover the amount you save (fuel) will be made up for in higher insurance for small car (liability rates). Simple physics!
 

yg17

macrumors G5
Aug 1, 2004
14,888
2,480
St. Louis, MO
Interesting Link.

I assume by engine off he means out of gear, not Engine off.. If you switch of the engine on most cars you would loose power stearing, power assisted brakes, ABS, and numerous other saftery features that may be taking power from the engine. Not a good idea.

Although I a gree with the general idea that keeping the momentum constant is the best way to consever fuel.

Wheaty
He might have meant engine off. You use more gas coasting out of gear than you do in gear. When you're out of gear, the engine must use some fuel to keep running. When you're in gear and coasting, the fuel injectors are turned off as the momentum of the wheels keeps the engine running. Plus, it's dangerous to coast out of gear.
 

Wheaty

macrumors regular
Mar 6, 2009
146
0
Cheshire, UK
He might have meant engine off. You use more gas coasting out of gear than you do in gear. When you're out of gear, the engine must use some fuel to keep running. When you're in gear and coasting, the fuel injectors are turned off as the momentum of the wheels keeps the engine running. Plus, it's dangerous to coast out of gear.
Hmmm. Maybe I'm miss understanding...

I think of engine off as Engine Switched off... No Ignition, No Fuel, No Otto Cycle, No Suck, Bang Squeese, Blow. etc
... In Gear this would lead to fairly brisk de-acceleration depending on engine specs.. Not exactly costing, although you wouldnt be using fuel either, unless engine driven fuel pumped car etc etc....

So by Engine off Do you think he means "Off the Gass"?
So everything is on, hes just not puting any more energy in than the car is using under its own in gear momentum and fuel mixture etc at that rev range/ speed etc..

Not trying to be too pedantic, (Not that fussed realy) But Its all a bit wooly..

Or My heads just feeling wooly today. One or the other...:)

Wheaty